Multiple stop for power tools

ABSTRACT

A shaft having a rotatable stop collar carrying adjustable stops is provided for a power tool, such as a drill press; it moves with the cutting tool, the stops being selectively registrable, optionally through an intermediate actuator, to bear against a stationary portion of the machine and/or an electrical limit switch for regulating depth of cut produced by the cutting tool.

[ 51 Apr. 3, 1973 United States Patent 1 Needham, Jr.

[54] MULTIPLE STOP FOR POWER TOOLS Primary Examiner-Francis S. HusarAttorney-Edward E. McCullough [76] Inventor: Andrew W. Needham, Jr., 141E. 3350 8., Salt Lake City, Utah 84115 Jan. 22, 1971 [21] Appl.No.:108,776

[22] Filed:

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UNITED STATES PATENTS 1,231,946 7/l9l7Schellenbach........;...............82/34 D r 2,361,453 ..29/65 X 15Claims, 11 Drawing Figures PATENTEU 3 I975 SHEET 1 [1F 3 FIGI!,\'\"E.\'TOR,

ANDREW W NEE DHAM JR 2M6 71 wm FIG IO AGENT PATENIEDAFRQ ms 13.724864SHEET 3 [1F 3 n 1 E l6 FIG. 9 INVENTOR.

ANDREW W. NEEDHAM JR,

AGEN T 1 MULTIPLE STOP FOR POWER TOOLS BACKGROUND OF THE INVENTION Thisinvention relates to automatic stop means for power tools. Inparticular, it relates to precision,'multiple stops, attachable to apower tool, that may be quickly selected and adjusted to regulate depthof cut in a work piece.

Although there are a number of devices in the prior art that areapplicable to power tools, such as drill presses, for regulating thedepth of cut produced by the cutting tool, no such device was found thatcould prov vide a selection of stops and that would be satisfactory foruse with a modern drill press. For example, U. S.

Pat. No. 971,679 to Kirby shows a multiple stop apparatus, but it isquite specifically applicable to a now obsolete type of drill press.Such stop means operate through linkages and arcuate motions that arenot compatible with present day requirements for precision. They alsoteach the use of shoulder pins that fit into holes in a carrier as thestop means, which is further lacking in precision because of thepossibility of foreign material becoming lodged between the shoulders ofthe pins and the carrier.

Other patents, such as a U. S. Pat. No. 2,110,537 to H. E. Tautz and U.S. Pat. No. 2,490,307 to M. J. Karr,

show single stop means for drill presses,- but do not show how these canbe adapted to multiple stop apparatus.

SUMMARY OF THE INVENTION The present invention, which has been developedto satisfy the need for a precision, multiple stop means for power toolsis an appliance that may be attached to a power tool, .such as a drillpress, lathe, or milling machine. Alternatively, it may be incorporatedas an integral part of the original machine. A shaft, attachable to amovable, cutting tool portionof a machine, has a rotatable collarcarrying adjustable stops that may bear against some stationary part ofthe machine. The

stops may also bear against an intermediate piece or sliding actuatorthat serves to operate a limit switch to cut off electrical power to themachine. By this means, depth of cut may be precisely regulated in awork piece.

Objects of the invention are to provide a means for precision control ofdepth of cut that is easily attachable to, or incorporated in, powertools and that offers rapid selection of any one of a variety of stops.

Important features of the invention are that it is simple and reliablein construction, and that it effects positive stops involving no motionsin any direction'other thanthat in which the cutting tool'moves.

Other objects and advantages of the invention will become apparent asthe following detailed description is read with reference to theaccompanying drawings, wherein the same parts are designated byidentical characters throughout the disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS only fragments of the machine to whichit is attached;

FIG. 3 is a view similar to FIG. 2 showing a simplified version thereof;

FIG. 4 is a cross section taken on line 44 of FIG. 2;

FIG. 5 is a full, longitudinal section taken on line 5- 5 of FIG. 4;

FIG. 6 is a cross section taken on line 6-6 of FIG. 2;

FIG. 7 is a fragmentary section showing a second species of stop;

FIG. 8 is a fragmentary section showing the stop of FIG. 7 in sideelevation;

FIG. 9 is a view similar to FIG. 8 showing a third species of stop;

FIG. 10 is a fragmentary section showing a fourth species of stop; and IFIG. 11 is a fragmentary side elevation of the invention as an integralpart of a drill press.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the invention isapplicable generally to power tools having movable cutting bits, thepreferred embodiment shown in the accompanying figures is attachable toa typical drill press 10. A shaft 11 is joined in parallel relationshipto a somewhat smaller diameter rod 12 by a yoke 13, forming a U-shapedmember. Both the shaft 11 and the rod 12 have smaller diameter threadedportions at one end, forming shoulders 14 and 15, respectively. Thesethreaded portions are inserted into holes in the yoke 13, which is thenconfined between the shoulders 14 and 15 and nuts 16. The shaft 11 androd 12 could be fastened to the yoke by other means, such as threadedengagement in the yoke itself without the nuts 16, or at least the shaft11 could be fastened by welding. A portion 17 of the movable carriage ofthe drill press, which carries the cutting bit 18 in verticaldirections, is confined between the shoulder 15 of the rod 12 and theyoke 13, so that the invention is carried in vertical directions withthe cutting bit 18. Hence, the shoulder 15, its threaded portion andcorresponding nut 16 are attachment means for fastening the U-shapedmember to the drill press. A sleeve 19 is fitted onto the shaft 11 andheld immobile thereon by the set screw 20. The sleeve 19 has a smallerdiameter portion 23, forming a shoulder 24; and it may also have athickened portion 25 to accommodate the set screw 20. A rotatable stopcollar 26 is confined'on the sleeve 19 between the shoulder 24 and asnap ring 27 that fits into an annular groove 28 in the sleeve 19. Itmay be noted that this combination of sleeve 19, its should 24,

snap ring 27 and set screw 20 comprise means of adjustably fixing thelongitudinal position of the stop collar 26 on the shaft 11. Aspring-loaded ball catch 29 is threadedly engaged in a radially orientedhole 30 in the collar 26, so that the ball thereof is biased inwardlyand may engage any one of a plurality of indentations 31 that arecircumfe rentially spaced about the sleeve 19 (FIGS. 4 and 5). Aplurality of stops 32 are carried by the collar 26 and are adjustablethereto in a direction on a projection 36 and an under surface is a camsurface 37 on an opposite projection 38. A pointer 39, that may operaterelative to the scale 40 on the drill press, is fixed to the shaft 11 bya small collar 41 having a set screw 42.

In operation of the invention, the operator first lowers the drill bit18 until it touches the workpiece, not shown, and adjusts the pointer 39until it registers with zero on the scale 40. He then places the slidingactuator 33 in contact with the stationary portion 43 of the drill press10, through which the rod 12 extends. Removing the workpiece from underthe drill bit 18, he rotates a selected stop 32 into alignment with thebearing surface 35 of the sliding actuator 33, raises that stop untilits lower end is flush with the under surface of the collar 26, andloosens the set screw 20 in the sleeve 19. Then, lowering the carriageof the drill press until the pointer 39 indicates somewhat more on thescale 40 than the depth of the deepest hole he intends to make, hetightens the setscrew 20. This insures that the collar 26 issufficiently high on the shaft 11 to permit the amount of travel neededfor all holes. He then lowers the carriage of the drill press 10 untilthe pointer 39 indicates the precise depth of the desired hole, andadjusts the selected stop 32 until it contacts the bearing surface 35.Rotating the collar 26, this procedure is preformed with as many of thestops 32 as are needed for automatic determination of holes of differentdepths. The indentations 31 in the sleeve 19 are spaced relative to theball catch 29 and the stops 32 so that the stops 32 may be quickly andselectively brought into exact alignment with the bearing surface 35 ofthe sliding actuator 33.

If considerable precision is desired in the hole depths regulated by thestops 32, a dial micrometer 44 may be fixed to the pointer 39 so thatits plunger 45 may contact each stop 32 as it is brought into alignmentwith the bearing surface 35. In FIG. 2, the micrometer is shown fixed tothe small collar 41. The portion of the shaft 11 under the set screw 42is flattened to prevent rotation of the collar 41 thereon, so that thepointer 39 and the micrometer plunger 45 may not be rotated out ofalignment with the scale 40 and the selected stop 32, respectively (FIG.6).

When the operator wishes to drill, he rotates the selected stop 32,representing the desired hole depth, into alignment with the bearingsurface 35, turns on the machine, and lowers the drill bit 18 into theworkpiece. When the appropriate depth has been reached, the stop 32 willcontact the bearing surface 35 of the sliding actuator 33 and will thenforce the actuator 33 against the stationary portion 43 of the drillpress to achieve a mechanical stop. The cam surface 37 willsimultaneously be forced against the limit switch 46, to achieve shutoffof electrical power to the machine.

It is important to note that, after the appropriate stop 32 has beenselected and rotated into a position of alignment with the bearingsurface 35, the only motions permitted for the parts of the inventionare in the direction of translatory motion of the drill bit 18. Hence,there are no rotations of parts or components of motion in any otherdirection to impair the precision with which hole depths may bedetermined.

FIG. 3 shows a modification of the invention wherein the rod 12 iseliminated, as is the yoke 13. For certain drill presses, the shaft 11can be attached directly to the portion 17 of the movable carriage. Inthis modification, the actuator 33 has a somewhat different form and islabeled 33'. It slides on the shaft 11 in much the same manner as theactuator 32 slides on the rod 12 in the previous embodiment. However,the bearing surface of the actuator 33 is on a long arm 47, which alsoserves to operate the limit switch 46. Otherwise, all parts areidentical to those of FIG. 2 and function in the same manner.

FIGS. 7 and 6 illustrate an alternate embodiment for the stops 32, andare labeled 32'. In this embodiment, the stops 32 may be quickly set byincrements determined by small serrations 48 on the side of the stopmember 32'. These serrations or teeth are engaged by a slide member 49,which is tapered somewhat in a longitudinal direction so that, as it ispressed inwardly, it may be wedged tightly between chosen teeth 48. Ascale 50 may also be included on this stop for ready indication ofadjustment relative to the upper surface of the collar 26. A knurledknob 51 assists in withdrawing and engaging the slide member 49. Thestop 32' is noncircular in cross section to prevent its rotationrelative to the collar 26, and a small head 22 on the top end preventsits falling through the hole in the collar 26 when not engaged by theslide 49.

FIG. 9 shows a third embodiment of the stop 32, here labeled 32". Thisstop member 32" is a plain rod 52 having a small head 53 on one endslightly larger in diameter to prevent its falling through theunthreaded hole 54 in the collar 26. A set screw, threadedly engaged inthe edge of the collar 26 and radially oriented to bear against the stop32", can fix its position quickly once it is determined. The stop 32"may also have a scale 55 on it for the same purpose as has beendescribed for that on the stop 32'.

It is sometimes helpful to have combinations of these different types ofstops in the same collar 26. For example, although the threaded stops 32can be adjusted with precision, the stops 32' or 32" may be adjustedvery rapidly, even though the hole depths to be regulated thereby mayvary greatly.

FIG. 10 shows a fourth embodiment of the stop 32, here labeled 32". Thisstop is a rack gear that fits into a hole in the collar 26 in much thesame manner as the other stops described. A pinion gear 57 on a shaft 58meshes with the rack-gear stop in the collar 26. A knurled handle 59 onthe and of the shaft 58, which extends radially through the collar 26,permits raising and lowering of the stop 32" by'rotation the handle Thisstop 32" may be fixed in place by a set screw 60, which extends into thecollar 26 from the edge thereof.

FIG. 11 shows how the invention may be incorporated as an integral partof a drill press. The projection portion 17' of the movable carriage issimply elongated to serve as a yoke and is provided with threaded holes61 in which the shaft 11 and rod 12 are engaged. Otherwise, all partsare identical to those described with reference to FIGS. I6 and functionin the same way. Lock washers, not shown may be used between theshoulders 14 and 15 and the modified carriage portion 17' to preventrotation of the shaft 1 1 and rod 12.

An invention has been described that'constitutes an advance in the artof machining with power tools. Although the descriptions of thepreferred embodiments have been specific with regard to detail,-itshould be noted'that many such details may be altered without departingfrom the scope of the invention as it is defined in the followingclaims.

The invention claimed is:

l. A multiple-stop apparatus for automatic control of the depth of cutin a workpiece, attachable to the movable cutting tool carriage of apower tool, having stationary parts including a bearing surface thereon,comprising:

a shaft attachable to the cutting tool carriage parallel to the travelthereof;

a rotatable collar on the shaft; 7

means for restricting longitudinal movement of the collar on the shaft;

a plurality of stops fastened to the collar and adjustable thereto inthe direction of travel of the cutting tool carriage, the shaft beingpositioned relative to the stationary bearing surface of the power toolso that any of the stops may be selectively placed in alignment with thebearing surface by rotating the collar, so that abutment of the selectedstop against the bearing surface restricts further movement of thecarriage;

pointer means; and 1 a scale adjacent the pointer means and parallel tothe travel of the carriage relative to a stationary part, the pointer'means being fixed to one of these members and the scale being fixed tothe other,

whereby travel of the carriage relative to the statool, whereby suchselective alignment may be quickly and accurately achieved.

3. The apparatus of claim 1 wherein the stops in the collar are screwsengaged in threaded holes circumferentially spaced in the collar.

4. The apparatus of claim 1 wherein at least one stop is a rod,noncircular in cross section, that fits slidably into ahole of the samenoncircular shape in the collar; and further includesserrations on oneside of the rod; and an elongated slide member, having a wedge-shapededge, slidably engaged in a slot extending into the collar from the edgethereof adjacent the serrations of the rod, whereby the stop may beadjusted incrementally by wedging the slide member between selectedserrations thereon.

5. The apparatus of claim 4 wherein the stop has an enlarged head at thetop end thereof, so that it cannot fall through its hole in the collarwhen the slide member is withdrawn, and wherein the stop has a scaleimprinted thereon for measuring its against the stop, relative to thestop may surface of the over a collar.

6. The apparatus of claim 1 wherein at least one stop is a rod, slidablyengaged in a hole in the collar; and further includes a set screw,radially oriented and threadedly engaged in the collar from the edgethereof so that it may bear against the stop, whereby the stop may bequickly adjusted over a wide range of hole depths.

7. The apparatus of claim 4 wherein the stop has an enlarged head at thetop end thereof, so that it cannot fall through its hole in the collarwhen the set screw is loosened, and wherein the stop has a scaleimprinted thereon for measuring its adjustment relative to the uppersurface of the stop collar.

8. The apparatus of claim 1 wherein at least one of the stops is a rackgear slidably engaged in a hole in the collar; and further includes apinion gear radially oriented in the collar in mesh with the rack gear;and a handle centrally attached to the pinion gear and extending beyondthe edge of the collar for rotating the pinion gear and adjusting thestop.

9. The apparatus of claim 1 including an arm slidably engaged on theshaft in keyed relationship therewith between the collar and thestationary bearing surface on the power tool and extending outwardlyfrom the shaft and shaped to be always in alignment with the stationa'rybearirig surface and a limit switch on the power tool, whereby both amechanical stop and a power shutoff may be achieved.

10. The apparatus of claim 1 including: a second collar on the shaft;means for v preventing longitudinal and rotational movement of thesecond collar on the shaft; and a plunger-type micrometer fixed to thecollar, the plunger being oriented to contact any one of the stopsselectively as the stop collar is rotated on the shaft, wherebyadjustment of the selected stop may be accurately measured. 1 1. Theapparatus of claim 1 further including a rod having threads on one end,the threaded portion being i of smaller diameter than the remainder ofthe rod to form a shoulder; a yoke having two holes therein to fastenthe shaft and rod together in parallel relationship, the shaft alsobeing threaded on one end similarly to the rod, and nuts to confine theyoke against said shoulders, and whereby a portion of the movablecarriage of the power tool may be confined between the yoke and one ofsaid shoulders; and

an actuator having the form of a body with a hole through which the rodextends, so that the actuator may slide freely thereon, the uppersurface of the actuator being a precision bearing surface on which theselected stop may bear, and the under surface being an actuating surfacefor operating a limit switch and for contacting the stationary portionof the drill press as the actuator is moved on the rod by the selectedstop.

12. A multiple stop apparatus attachable to a drill press-having astationary portion and a movable carriage that holds a cutting tool,comprising:

a U-shaped member formed by a shaft, a rod, and a yoke joining themtogether;

attachment means for fastening the U-shaped member to the movablecarriage of the drill press parallel to the travel thereof;

a sleeve on the shaft, having circumferentiallyspaced indentationstherein;

adjustment means for adjusting the longitudinal position of the sleeveon the shaft and fixing it in a desired position;

a stop collar rotatably positioned on the sleeve and havingcircumferentially spaced holes therein;

means for restricting the longitudinal position of the collar on thesleeve;

a spring-loaded ball catch radially oriented in the stop collar so thatthe ball thereof may be partially forced into a selected one of theindentations in the sleeve, as the collar is rotated;

a plurality of stops adjustably engaged in the holes in the collar in adirection parallel to the shaft; and

a sliding actuator having the form of a body with a hole therethrough onthe rod between the stop collar and the stationary portion of the drillpress, portions of the actuator being simultaneously alignable with aselected stopand with said stationary portion, whereby a positivemechanical restraint will result as the stop approaches the stationaryportion, to regulate the cutting depth in a work piece.

13. The multiple stop apparatus of claim 12 wherein at least one of theadjustable stops in the stop collar has external screw threads and thehole in the collar in which it is engaged is also threaded, for positiveengagement and adjustment of the stop therein.

14. in a drill press having a stationary portion and a movable carriageholding a drill bit, the improvement comprising:

a yoke fixed to the movable carriage and formed as a projection thereon;

a shaft fixed to the yoke and oriented parallel to the motion of thecarriage;

a rod fixed to the yoke parallel to the shaft;

a rotatable stop collar on the shaft;

means for adjustably fixing the longitudinal position of the stop collaron the shaft;

a plurality of stops carried by the collar and adjustable theretoparallel to the motion of the carriage;

a sliding actuator on the rod, and having a bearing surface and anactuating surface thereon, the shaft and collar being positionedrelative to the bearing surface of the actuator so that any one of thestops may be rotated into alignment therewith, and the actuator being inalignment with the stationary portion of the drill press, whereby depthof the drill bit in a work piece may be automatically determined.

15. The drill press of claim 14 further including:

an electric limit switch on the stationary portion thereof, and inalignment with the bearing surface of the sliding actuator, wherebyelectric power may be turned off when appropriate depth of cut has beenachieved;

a scale on a stationary part of the drill press, ar-

ranged parallel to motion of the carriage; and

a pointer on the shaft arranged to indicate positions on the scale.

1. A multiple-stop apparatus for automatic control of the depth of cutin a workpiece, attachable to the movable cutting tool carriage of apower tool, having stationary parts including a bearing surface thereon,comprising: a shaft attachable to the cutting tool carriage parallel tothe travel thereof; a rotatable collar on the shaft; means forrestricting longitudinal movement of the collar on the shaft; aplurality of stops fastened to the collar and adjustable thereto in thedirection of travel of the cutting tool carriage, the shaft beingpositioned relative to the stationary bearing surface of the power toolso that any of the stops may be selectively placed in alignment with thebearing surface by rotating the collar, so that abutment of the selectedstop against the bearing surface restricts further movement of thecarriage; pointer means; and a scale adjacent the pointer means andparallel to the travel of the carriage relative to a stationary part,the pointer means being fixed to one of these members and the scalebeing fixed to the other, whereby travel of the carriage relative to thestationary part may be measured.
 2. The apparatus of claim 1 furtherincluding a spring-loaded, ball catch fastened to the collar radially sothat the ball thereof is urged inwardly toward the shaft, which hasindentations into which the ball may be partially forced, to providerotational stop means for the collar on the shaft, the number andspacing of the indentations relative to the ball catch and theadjustable stops being such as to bring any selected stop into alignmentwith the stationary bearing Surface on the power tool, whereby suchselective alignment may be quickly and accurately achieved.
 3. Theapparatus of claim 1 wherein the stops in the collar are screws engagedin threaded holes circumferentially spaced in the collar.
 4. Theapparatus of claim 1 wherein at least one stop is a rod, noncircular incross section, that fits slidably into a hole of the same noncircularshape in the collar; and further includes serrations on one side of therod; and an elongated slide member, having a wedge-shaped edge, slidablyengaged in a slot extending into the collar from the edge thereofadjacent the serrations of the rod, whereby the stop may be adjustedincrementally by wedging the slide member between selected serrationsthereon.
 5. The apparatus of claim 4 wherein the stop has an enlargedhead at the top end thereof, so that it cannot fall through its hole inthe collar when the slide member is withdrawn, and wherein the stop hasa scale imprinted thereon for measuring its against the stop, relativeto the stop may surface of the over a collar.
 6. The apparatus of claim1 wherein at least one stop is a rod, slidably engaged in a hole in thecollar; and further includes a set screw, radially oriented andthreadedly engaged in the collar from the edge thereof so that it maybear against the stop, whereby the stop may be quickly adjusted over awide range of hole depths.
 7. The apparatus of claim 4 wherein the stophas an enlarged head at the top end thereof, so that it cannot fallthrough its hole in the collar when the set screw is loosened, andwherein the stop has a scale imprinted thereon for measuring itsadjustment relative to the upper surface of the stop collar.
 8. Theapparatus of claim 1 wherein at least one of the stops is a rack gearslidably engaged in a hole in the collar; and further includes a piniongear radially oriented in the collar in mesh with the rack gear; and ahandle centrally attached to the pinion gear and extending beyond theedge of the collar for rotating the pinion gear and adjusting the stop.9. The apparatus of claim 1 including an arm slidably engaged on theshaft in keyed relationship therewith between the collar and thestationary bearing surface on the power tool and extending outwardlyfrom the shaft and shaped to be always in alignment with the stationarybearing surface and a limit switch on the power tool, whereby both amechanical stop and a power shutoff may be achieved.
 10. The apparatusof claim 1 including: a second collar on the shaft; means for preventinglongitudinal and rotational movement of the second collar on the shaft;and a plunger-type micrometer fixed to the collar, the plunger beingoriented to contact any one of the stops selectively as the stop collaris rotated on the shaft, whereby adjustment of the selected stop may beaccurately measured.
 11. The apparatus of claim 1 further including arod having threads on one end, the threaded portion being of smallerdiameter than the remainder of the rod to form a shoulder; a yoke havingtwo holes therein to fasten the shaft and rod together in parallelrelationship, the shaft also being threaded on one end similarly to therod, and nuts to confine the yoke against said shoulders, and whereby aportion of the movable carriage of the power tool may be confinedbetween the yoke and one of said shoulders; and an actuator having theform of a body with a hole through which the rod extends, so that theactuator may slide freely thereon, the upper surface of the actuatorbeing a precision bearing surface on which the selected stop may bear,and the under surface being an actuating surface for operating a limitswitch and for contacting the stationary portion of the drill press asthe actuator is moved on the rod by the selected stop.
 12. A multiplestop apparatus attachable to a drill press having a stationary portionand a movable carriage that holds a cutting tool, comprising: a U-shapedmember formed by a shaft, a Rod, and a yoke joining them together;attachment means for fastening the U-shaped member to the movablecarriage of the drill press parallel to the travel thereof; a sleeve onthe shaft, having circumferentially-spaced indentations therein;adjustment means for adjusting the longitudinal position of the sleeveon the shaft and fixing it in a desired position; a stop collarrotatably positioned on the sleeve and having circumferentially spacedholes therein; means for restricting the longitudinal position of thecollar on the sleeve; a spring-loaded ball catch radially oriented inthe stop collar so that the ball thereof may be partially forced into aselected one of the indentations in the sleeve, as the collar isrotated; a plurality of stops adjustably engaged in the holes in thecollar in a direction parallel to the shaft; and a sliding actuatorhaving the form of a body with a hole therethrough on the rod betweenthe stop collar and the stationary portion of the drill press, portionsof the actuator being simultaneously alignable with a selected stop andwith said stationary portion, whereby a positive mechanical restraintwill result as the stop approaches the stationary portion, to regulatethe cutting depth in a work piece.
 13. The multiple stop apparatus ofclaim 12 wherein at least one of the adjustable stops in the stop collarhas external screw threads and the hole in the collar in which it isengaged is also threaded, for positive engagement and adjustment of thestop therein.
 14. In a drill press having a stationary portion and amovable carriage holding a drill bit, the improvement comprising: a yokefixed to the movable carriage and formed as a projection thereon; ashaft fixed to the yoke and oriented parallel to the motion of thecarriage; a rod fixed to the yoke parallel to the shaft; a rotatablestop collar on the shaft; means for adjustably fixing the longitudinalposition of the stop collar on the shaft; a plurality of stops carriedby the collar and adjustable thereto parallel to the motion of thecarriage; a sliding actuator on the rod, and having a bearing surfaceand an actuating surface thereon, the shaft and collar being positionedrelative to the bearing surface of the actuator so that any one of thestops may be rotated into alignment therewith, and the actuator being inalignment with the stationary portion of the drill press, whereby depthof the drill bit in a work piece may be automatically determined. 15.The drill press of claim 14 further including: an electric limit switchon the stationary portion thereof, and in alignment with the bearingsurface of the sliding actuator, whereby electric power may be turnedoff when appropriate depth of cut has been achieved; a scale on astationary part of the drill press, arranged parallel to motion of thecarriage; and a pointer on the shaft arranged to indicate positions onthe scale.